1. Field of the Invention
The present invention relates to a marine vessel propulsion device including a jet propulsion unit that jets water to generate a propulsive force and to a marine vessel including such a marine vessel propulsion device.
2. Description of Related Art
A conventional marine vessel that includes a jet propulsion unit is disclosed in U.S. Pat. No. 5,755,601. The marine vessel includes a hull, a steering assembly, an engine, a jet pump (jet propulsion unit), a thrust guide, and a reverse gate. The jet pump has a nozzle that jets water toward a rear of the hull. The thrust guide is attached to the reverse gate so as to be pivotable to the right and left. The thrust guide is arranged to orient a direction of the water jetted from the nozzle. When the steering assembly is operated by a marine vessel operator, the thrust guide pivots to the right and left in linkage with the operation.
The reverse gate is attached in a vertically pivotable manner to flanges that are fixed to the nozzle. The reverse gate is arranged to be pivotable between a forward position (full-up position) and a reverse position (full-down position). The reverse position is located at a rear of the thrust guide and is a fully closed position at which the reverse gate covers an entirety of an opening of the thrust guide. When positioned at the reverse position, the reverse gate covers the entirety of the opening of the thrust guide and reverses the water, jetted from the nozzle and through the thrust guide, to a forward direction. A propulsive force in a reverse direction is thereby applied to the hull. The forward position is located above the reverse position and is a fully opened position at which the reverse gate does not cover the opening of the thrust guide at all. When positioned at the forward position, the reverse gate does not block the water jetted from the jet nozzle and thus a propulsive force in the forward direction is applied to the hull. The reverse gate can be positioned at a neutral position between the forward position and the reverse position. At the neutral position, the forward direction propulsive force and the reverse direction propulsive force are substantially balanced and the hull can thus be maintained in position.
A right lever for throttle control and a left lever for deceleration control are attached to the steering assembly. When the right lever is operated without operating the left lever, the reverse gate is positioned at the forward position. When the left lever is operated without operating the right lever, the reverse gate is positioned at the reverse position. When both the right and left levers are operated, the reverse gate is positioned at the neutral position. A throttle opening degree of the engine is mechanically linked to the lever operations by throttle cables coupled to the right and left levers.